In a 2010 survey by the same government body, 68 percent of Japanese 18-19 year olds said they were virgins; a study carried out that year in Europe by condom maker Durex found virginity rates among those aged 15-20 were much lower.

For example, fewer than 20 percent of young Germans had not had sex by the time they hit 20, while even in socially conservative Turkey, the figure was only 37 percent.

Japan's apparently low libido sits at odds with the impression many visitors have about the country's attitude to sex.

Images of impossibly busty -- and frequently underdressed -- young women are common in the ubiquitous manga comics and on billboards.

Prostitution is readily visible in even smaller cities and the country produces voluminous amounts of often eyebrow-raising pornography.

Futoshi Ishii, who heads the body that carried out the sex survey said the root of the issue seemed to be the gulf between how people imagine life should be and how it actually turns out.

«They want to tie the knot eventually," he told the Japan Times. "But they tend to put it off as they have gaps between their ideals and the reality,»